The present invention relates to formation of semiconductor structures and more particularly, to wet strippable gap fill materials for multilayer patterning schemes.
Various applications in 10, 7, 5 nanometer (nm) lithography and beyond require the fill of and planarization over small features or crevices printed and etched into various lithographic substrates. The dimensions of these features shrink with the lithographic node, which generally means that it becomes more and more challenging to fill these features and crevices. The removal of the gap fill materials after processing of the lithographic steps involving them typically involves reactive ion etch (RIE).
Typically, underlayers such as organic planarizing layers (OPL) materials, also known as spin-on carbon materials, as well as spin on silicon containing materials are irreversibly crosslinked during the post apply bake (PAB) in order to prevent their dissolution during the application of the next spin-coated layer.